HTML Introduction
In this first section, we'll be looking at
- Client-Server Architecture
- Uniform Resource Locators
- Hypertext Markup Language
- HTML Tags
What is Client-Server Architecture?
- The WWW protocols follow the client-server model of
computing. When surfing the web, the following process
occurs:
- Client software (the web browser running on your
desktop computer) connects to a web server, and
requests a copy of a file that resides on that
server.
- The Server then performs several tasks:
- acknowledges the client's attempt to
connect
- sends a copy of the requested file
(whether it's an HTML document, image,
sound, etc.)
- breaks the connection to the client
- The Client software receives and displays the
file on the user's desktop. There is no longer
any connection whatsoever to the web server.
Since the processing is split between the client
software and the server software, both computers'
resources can be more efficiently utilized. It also means
that the user won't see any changes that are made to a
file while they are viewing it. The user would have to
"Reload" the file, i.e., request a current copy
of the file from the web server.
What are URLs?
- Uniform Resource Locators are the unique addresses or
locations of resources on the Internet. When you hear
'URL,' think 'street address': just like the pizza
delivery driver needs to know your address to deliver
your pizza, your browser needs to know the URL of the web
site to get there. A URL consists of
"pathnames" to files located on computers
throughout the world. URLs consist of three parts which
are all CASE SENSITIVE:
- the protocol to be used to identify the retrieval
method (in this case the HyperText Transfer
Protocol):
- http://
- an address identifying the machine on which the
file resides:
- skyways.lib.ks.us
- the path to the directory where the item is
located on that machine, and the file's name.
- /kansas/training
The full URL looks like this : http://skyways.lib.ks.us/kansas/training/intro_html.html
What is HTML?
- HTML is short for Hypertext Markup Language. It's not
programming, but a method of assigning "tags"
to text and images so they'll display in a web document.
HTML
is based on SGML (Standard Generalized Markup Language),
which is used to describe the general structure of
various kinds of documents, and is being used in the
creation of digital libraries. Browsers (such as
Netscape), or to use the lingo, clients,
take the formatting tags in an HTML document and arranges
it into what you see when a web page is loaded.
Different browsers will format the same HTML tags in
different ways, and users can change preferences in their
browsers that affect the way web pages look. For this
reason, web page design must be well structured and
adhere to HTML standardization.
What Are Tags?
- Tags are the tools used to create an HTML document and to
format text for an internet browser. There are
"beginning" and "ending" tags
(covered here) and "empty tags."
Tag Descriptions
Beginning and Ending Tags
- The purpose of beginning and ending tags is to begin and
end changes to a web document and to text and graphics
that appear on the page. If you begin an effect (such as
making text bold), you have to turn it off at some point.
Ending tags are typically the same as the beginning tags
except they contain a frontslash (/). For example, the
heading that proceeds this paragraph is tagged as
follows:
<STRONG>Beginning
and Ending Tags</STRONG>
The <STRONG> tag assigns a bold text
attribute which is ended by the </STRONG>
tag.
<HTML></HTML>
- The <HTML> tag appears at the top of your
HTML document as the first tag. This tag tells a web
browser to display an HTML document. The <HTML>
tag ends with </HTML> as the last tag in
an HTML document.
<HEAD></HEAD>
- The <HEAD> tag appears directly after <HTML>
and encloses the document title. Within Pulse (see
"Unique Pulse HTML Requirements" below) it also
encloses information about the document Author, Contact
Person, Department, Expiration Date and Keyword
information. The <HEAD> tag ends with </HEAD>.
<TITLE></TITLE>
- The <TITLE> tag appears between the <HEAD></HEAD>
tags and contains a document title that you assign and
which appears in the browser title bar. The <TITLE>
tag ends with </TITLE>.
<BODY></BODY>
- The main content of your document begins with the <BODY>
tag and ends with the </BODY> tag.
Information such as document background colors and
background patterns can also be assigned within the </BODY>
tag. The </BODY> tag appears next-to-last
just prior to the </HTML> tag.
We've now reviewed the key "tags" that make up the
"shell" of a web document. Now take a look at these
tags in action:
ASSIGNMENT: Paste
the following into WordPad to create a web document. Save the
file to your disk and name it 'yourlastname.html'. Then open the
file in Netscape. We will build on this same document throughout
this tutorial.
<HTML>
<HEAD>
<TITLE>Library or Town Name</TITLE>
</HEAD>
<BODY>
Replace this text with whatever you want.
</BODY>
</HTML>
Above: an HTML document
"shell"
Move on to Section Two
of the training